Raloxifene

How it works

Raloxifene (Evista) is another drug in the class known as SERMs. It's also prescribed in pill form, to be taken by mouth once a day for five years.

Like tamoxifen, raloxifene works by blocking estrogen's effects in the breast and other tissues. Unlike tamoxifen, raloxifene doesn't exert estrogen-like effects on the uterus.

Who it's for

Raloxifene is used to reduce the risk of invasive breast cancer in high-risk women who are past menopause (postmenopausal). You're considered at high risk if you score greater than 1.66 percent on the Gail model.

Raloxifene is also used for prevention and treatment of the bone-thinning disease osteoporosis in postmenopausal women.

Common side effects

Common side effects of raloxifene include:

Hot flashes

Vaginal dryness or irritation

Joint and muscle pain

Weight gain

Risks

Health risks associated with raloxifene are similar to those associated with tamoxifen.

Both drugs carry an increased risk of blood clots, though the risk may be lower with raloxifene. However, raloxifene may be associated with fewer cases of endometrial and uterine cancers than is tamoxifen.

Raloxifene may also be linked to fewer strokes than tamoxifen in women at average risk of heart disease. But if you have heart disease or you have multiple risk factors for heart disease, raloxifene may increase your risk of strokes.

Although tamoxifen may be slightly better than raloxifene at reducing the risk of breast cancer, the risk of blood clots and uterine cancer also may be lower with raloxifene. For this reason, raloxifene may be a preferred option for women who have undergone menopause and who haven't undergone a hysterectomy or who have osteoporosis.

Aromatase inhibitors

Aromatase inhibitors are commonly used to treat breast cancer that's hormone receptor positive in postmenopausal women. These drugs are also an option for breast cancer chemoprevention.

How they work

Aromatase inhibitors are a class of medicines that reduce the amount of estrogen in your body, depriving breast cancer cells of the fuel they need to grow and thrive.

Three aromatase inhibitors are currently approved for use in the treatment of postmenopausal women with breast cancer: anastrozole (Arimidex), exemestane (Aromasin) and letrozole (Femara).

These medications are used to treat breast cancer in postmenopausal women with estrogen- or progesterone-responsive tumors.

Who they're for

Aromatase inhibitors have been studied and shown to be effective in postmenopausal women to treat breast cancer and to prevent breast cancer recurrence. Aromatase inhibitors are not intended for preventing breast cancer recurrence in women who still have menstrual cycles.

Aromatase inhibitors have been studied to see if they may reduce the risk of breast cancer in high-risk women, such as those with a family history of breast cancer or a history of precancerous breast lesions. Studies have shown promise in these high-risk women.

Based on these results, some women and their doctors may choose to use aromatase inhibitors to reduce the risk of breast cancer, though these drugs aren't approved for this use.

Additional studies are underway to determine whether aromatase inhibitors may reduce the risk of breast cancer in women with genetic mutations that increase the risk of breast cancer.

Common side effects

Common side effects of aromatase inhibitors include:

Hot flashes

Vaginal dryness

Joint and muscle pain

Headache

Fatigue

Risks

Aromatase inhibitors raise the risk of bone thinning (osteoporosis).

Aromatase inhibitors aren't associated with an increased risk of blood clots or uterine cancer, as tamoxifen and raloxifene are. Because aromatase inhibitors are a newer class of medications, not much is yet known about long-term health risks, such as heart disease and broken bones (fractures).

As more results from research studies become available, doctors will have a better idea of the long-term health implications for these drugs and their effectiveness in breast cancer chemoprevention.

Legal Conditions and Terms

Reprint Permissions

A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.org," "Mayo Clinic Healthy Living," and the triple-shield Mayo Clinic logo are trademarks of Mayo Foundation for Medical Education and Research.